Utility of Biomarkers in Sepsis

Background: Sepsis constitutes a substantial burden on global health, characterized by high rates of morbidity and mortality.The absence of a universally accepted diagnostic gold standard poses a significant clinical challenge.Blood cultures are slow, so biomarkers are crucial for early detection and risk assessment.We hypothesized that a combination of interleukin-6 (IL-6) and ferritin along with procalcitonin (PCT) increases the diagnostic accuracy in sepsis.Our aim was to evaluate the diagnostic and prognostic accuracy of biomarkers [PCT, IL-6, ferritin, C-reactive protein (CRP)] in differentiating between culture-positive and culture-negative sepsis and to determine the relationship of biomarkers with the severity assessment scoring systems.Methodology: An observational study conducted on 100 adult sepsis patients in a tertiary care intensive care unit (ICU).Blood, urine, tracheal aspirate, and other body fluid samples for biomarkers of sepsis and microbiological studies were collected.Patients were categorized based on culture results.Primary outcome was survival or death of participant, and secondary outcome was the number of days of ICU stay. Results:The study revealed that gram-negative sepsis was most common, with Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii as the primary pathogens.When compared to PCT, the diagnostic accuracy of IL-6, ferritin, and CRP was 67, 60, and 50%, respectively.Combinations of biomarkers, particularly PCT with IL-6 (p = 0.004) or ferritin (p = 0.025), were more predictive of gram-negative sepsis than individual biomarkers.Increased IL-6 level was significantly associated with adverse outcome (p = 0.001).Severity scores, namely acute physiology and chronic health evaluation (APACHE II), quick sequential organ failure assessment (qSOFA), sequential organ failure assessment (SOFA), and national early warning score (NEWS2), were all statistically significant in predicting adverse outcomes (p < 0.001) in our study. Conclusion:A panel of sepsis biomarkers, especially when combined, can improve early diagnosis and risk stratification in sepsis.Point-of-care testing of these biomarkers can aid clinicians in making timely treatment decisions.Future research should explore the integration of biomarkers into machine learning algorithms for more accurate sepsis diagnosis. Highlights:Biomarker assay panel may be utilized as adjunct to cultures in management of sepsis.Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii are common pathogens of gram-negative sepsis.Sensitivity and specificity of PCT = 46.2 and 59.5%, CRP = 88.5 and 24.3%, IL-6 = 57.7 and 78.4%, and ferritin = 69.2 and 45.9%, respectively.IL-6 (AUROC = 0.782) was best for prognostication of sepsis and statistically significant in predicting outcome of participants (p = 0.001).Combination of PCT with either CRP (p = 0.005), IL-6 (p = 0.004), or ferritin (p = 0.025) could predict gram-negative sepsis earlier than culture sensitivity reports.Severity scores (APACHE II, qSOFA, SOFA, NEWS2) were all statistically significant in predicting outcomes (p < 0.001).